PPRuNe Forums - View Single Post - 787 Batteries and Chargers - Part 1
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Old 15th Mar 2013, 16:55
  #990 (permalink)  
Ian W
 
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,346
Lyman
Sinnett chose his prose carefully, for what he means is there will be no "Aircraft FIRE", not "No Battery FIRE...."

That makes his comment sleazy, sly, and at least to me, dishonest....
I think you may be getting a little overexcited for the Tech Log thread and even for the R&N thread.

From the briefing:
During engineering testing, which occurs prior to certification testing, the team demonstrated that the new housing could safely contain a battery failure that included the failure of all eight cells within the battery. The "ultimate" load is the equivalent of 1.5 times the maximum force ever expected to be encountered during a battery failure. The housing easily withstood this pressure and did not fail until the pressure was more than three times the ultimate load.
Through another test, the team demonstrated that fire cannot occur within the new enclosure. Its design eliminates oxygen, making the containment unit self-inerting. Inerting is a step above fire detection and extinguishing as it prevents a fire from ever occurring. The design also vents all vapors by venting directly outside of the airplane rather than into the equipment bay.
"We put this new design through a rigorous set of tests. We tried to find a way to introduce a fire in the containment but it just wouldn't happen. Even when we introduced a flammable gas in the presence of an ignition source, the absence of oxygen meant there was no fire.
"We drew from the new industry standard, DO311, established by RTCA, to establish our testing plan," said Sinnett. "These standards weren't available when we set the testing plan for the baseline battery and they helped us ensure the new design is robust and safe. We intend to show, during certification, that the 787 battery meets all objectives of DO-311 and only deviates from specific requirements where the 787-unique items are not covered by the standards." RTCA is a not-for-profit organization that serves as a federal advisory committee in establishing guidelines for the aviation industry.
What is it about demonstrating that fire cannot occur inside the new enclosure that you fail to grasp?

These guys who are internal and external experts on these batteries seem to have accepted that they don't know what caused the problems but have grouped potential causes for problems into categories then ensured that those causes do not cause the battery problems and -even it they did- any battery issue would be safely contained without fire.

The FAA is not going to be caught out again 'not testing enough' and nor is EASA so you can be assured that this is not a 'political' fix.

Would you prefer Boeing just left all the 787s on the ground until they can be rebuilt with canvas covered wood stringers and radial engines with propellers? Or would the danger of a gasoline fire in a wooden aircraft make you stick to ground travel?
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